Geospatial for Conservation of Aravali Hills against Urban Development in Udaipur Region, Rajasthan, India

Abstract. The city of Udaipur is situated amidst the southern Aravali hills in the state of Rajasthan in India. The State hill policy governs urban development on these hills. The policy lacks transparent, objective and verifiable criteria, and a methodology for delineating the Hill Top Hill Slope (HTHS) and ‘no construction’ zones. This has resulted in widespread construction on the hills in recent years. This study examines the chronology and status of urban development on the Aravali hills in the Udaipur Development Authority (UDA) region using the CORONA datasets, Google Earth historical imageries and ESRI satellite basemap. More than 140 development sites have been mapped, which occur from the foothill zones to slopes more than 20° and elevations more than 700 m above mean sea level. A robust geospatial workflow for delineating the HTHS has been proposed. Vertical accuracy of openly available Digital Elevation Models (DEMs) - SRTM v 3.0, FABDEM v 1-2, and ALOS PALSAR - has been ascertained using visual analytics and error metrics taking along track profile of ICESat-2 data as reference data. FABDEM has provided highest vertical accuracy in the hilly area. Overlay of slope, elevation and contour maps generated from FABDEM effectively delineates the HTHS region and identifies terrain characteristics of existing constructed sites. Decisions on proposals for new development can be taken based on overlay of cadastral boundary or coordinates of proposed site on HTHS map. The suggested geospatial workflow can aid in framing and enforcing an effective hill policy for conservation of hills.